Sick hen any ideas?

I bought 16 new road Island reds last Sunday. they were all well and healthy, feathers appetite, eyes and skin. No sign of illness whatso ever. I live in Texas and the temps are upper 20's to high 70's fluctuating in between the two. I noticed Friday I had one hen that's comb turned pale and she sat squatted all day in the sun and did not eat or drink. I isolated her in my quarantine pen with food and water and a heat light in the corner. She passed overnight. Today I have another hen who is squatting fluffed up and drank a little this morning but wants to be alone away from the other chickens. Her comb is red not discolored and she is not making any strange noises, just doesn't feel good. Any ideas? I do not want to lose another one.

I would treat them with Corid for possible coccidiosis. There are at least 9 strains in chickens, and the move to your soil may have exposed them to a different strain. Corid dosage is 2 tsp of the liquid, or 1.5 tsp of the powder per gallon of water for 5-7 days. Make sure they are drinking the solution, or feed it with a dropper. How old are they? Do you know if they have ever been wormed? Check their skin all over for evidence of mites or lice.